Law enforcement or regulator agencies, such as the FBI, police, SEC, in the course of investigating potentially criminal activities have a need to correlate one or more telephone numbers to associated subscribers' name and address. For example, a law enforcement agency may first obtain a list of telephone numbers that a person under investigation has called. A law enforcement agency may be interested in knowing information about the persons called to determine additional parties that may be involved in a suspected criminal activity. A law enforcement agency may subpoena telephone company records to obtain the name and address of the called party by issuing a subpoena. After a called party's name and address is known from the telephone company records, the law enforcement agency can contact the called party. For example, a law enforcement agency can issue a second subpoena to compel a called party to appear at a specified place and time to answer questions or provide additional information.
Searching for a subscriber's name and address using reverse directories is well known in the art. These directories are available from the telephone company directory assistance and numerous Internet web sites. However, these databases only provide current subscriber information. Records of previous telephone companies or subscribers assigned a specified telephone number are not readily available. In addition, subscriber's can block access of their telephone number from the public records, and consequently, the Internet web sites. Hence, to obtain a subscriber's name and address, law enforcement agencies must subpoena subscriber information directly from the subscriber's telephone company. The subscriber's telephone company can be easily determined from available records by using the assigned Number Plan Area-Central Office Code, i.e., NPA-NXX. Number Plan Area (NPA) numbers are assigned by the North American Number Plan Administration and are commonly referred to as “area codes.” Central Office Code (NXX) numbers are commonly referred to as “telephone exchanges.” For example, “212-884” refers to the 884 telephone exchange in New York City, i.e., area code 212.
When there were relatively few telephone companies and one telephone company was assigned the majority of subscribers in a state, the process of determining an appropriate telephone company using a reverse directory was a relatively straight-forward process. However, telephone deregulation and recent rule changes have contributed to an increase in the number of telephone companies. And, consequently, an increase in the complexity of quickly, and accurately, determining the appropriate telephone company using a reverse telephone directory search. For example, telephone deregulation has significantly increased the number of telephone companies that are assigned NPA-NXX numbers. Currently, the pool of NPA-NXX numbers are assigned to companies such as Verizon, BellSouth, Highland Telephone Cooperative, etc., which are LECs (Local Exchange Carriers). In addition, telephone numbers are assigned to smaller telephone companies, such as, CLECs (Competitive Local Exchange Carriers), wireless companies, and paging companies. Many of these companies did not exist when the telephone company reverse records were first employed. Further, the Federal Communication Commission (FCC) has changed the rules for issuing telephone numbers from a minimum of 10,000 numbers (i.e., the four digits of the telephone after the NXX exchange number) to a minimum of 1,000 numbers (“thousand line pooling”). Hence, telephone numbers that were in the past assigned to a single telephone company can now be assigned to up to ten different companies. Further, the FCC requires that telephone numbers that have not been used by an assignee telephone company are returned, i.e., given back. The returned numbers can then be assigned to another company.
Thus, when a law enforcement agency is required to determine a subscriber name and address from a telephone number, the agency must first determine the appropriate telephone company assigned to the telephone number at the time of interest. Otherwise, the subscriber name and address obtained from an incorrectly determined telephone company results in the wrong subscriber being subpoenaed or questioned. This incorrect determination of the telephone company and subscriber burdens the agency, and telephone companies, as valuable time is lost while the reverse directory search is repeated and resources are expended on needless questioning and interviewing. Hence, there is a need to provide reverse directory searches that are performed in a timely, and efficient, manner and provide accurate telephone company NPA-NXX telephone assignment.